Android Studio Battery Checker 2-4

BatteryReceiver.java

public class BatteryReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {

        /* 省略 */

        if (action != null && action.equals(Intent.ACTION_BATTERY_CHANGED)) {

            /* 省略 */

            // 画像を表示
            if (percentage >= 90) {
                batteryImage.setImageResource(R.drawable.b100);

            } else if (percentage >= 65) {
                batteryImage.setImageResource(R.drawable.b75);

            } else if (percentage >= 40) {
                batteryImage.setImageResource(R.drawable.b50);

            } else if (percentage >= 15) {
                batteryImage.setImageResource(R.drawable.b25);

            } else {
                batteryImage.setImageResource(R.drawable.b0);
            }
        }

    }
}